This invention relates to valves of the rotary plug type and more particularly concerns a valve which has a metal body with inlet and outlet ports and a plug chamber comprising an opening extending through said body in perpendicular relation to said ports, a valve plug rotatably mounted in said chamber having a transverse passage selectively to move into and out of register with said port holes upon rotation of the plug, and means including a knob on one end of the plug coactive with the valve body for separably holding said plug in operative position in the valve body.
Valves of this general nature are widely known in the prior art, as shown for example, by U.S. Pat. Nos. 3,223,111; 3,173,648; 2,982,148, and my U.S. patent No. 3,787,028. These and other prior art valves provide so-called leak-proof means to reduce the possibility of leakage of fluid between the ports in the valve body and the rotary plug but such means either do not provide certainty of no leakage, or are too expensive, or are too difficult to manufacture, or are too difficult to assemble and to take apart, or hinder rotation of the plug.